GM Service Manual Online
For 1990-2009 cars only

Step

Action

Yes

No

Schematic Reference: Headlights/Daytime Running Lights (DRL) Schematics

Connector End View Reference: Lighting Systems Connector End Views

1

Did you perform the Diagnostic System Check - Vehicle?

Go to Step 2

Go to Diagnostic System Check - Vehicle

2

  1. Place the headlamp switch in the HEADLAMP position.
  2. Place the headlamp dimmer switch in the LOW position.
  3. Place the headlamp dimmer switch in the HIGH position.

Do the appropriate headlamps illuminate in both headlamp dimmer switch positions?

Go to Testing for Intermittent Conditions and Poor Connections

Go to Step 3

3

  1. Disconnect the lighting high low relay.
  2. Probe the switch side output circuit of the lighting high low relay with a test lamp that is connected to battery positive voltage.

Does the test lamp illuminate?

Go to Step 4

Go to Step 5

4

Inspect for poor connections at the lighting high low relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs .

Did you find and correct the condition?

Go to Step 7

Go to Step 6

5

Repair an open or high resistance in the switch side output circuit of the lighting relay. Refer to Circuit Testing and Wiring Repairs .

Did you complete the repair?

Go to Step 7

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6

Replace the lighting high low relay.

Did you complete the replacement?

Go to Step 7

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7

Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3